Posted By Tyler Hi all and Season's Greetings! Questions. One of our suppliers has a preferred method of offloading sodium hypochlorite (bleach). The contents of IBCs (that remain on the back of their HGV) are offloaded by applying a small amount of pressure in the IBC using nitrogen gas which then forces the IBC contents through the pipes and into our vessel on site. Sounds fine but. Does anyone have any experience of this technique? What assurances and documentation should I be requesting from the supplier / delivery company? (Pressure check certificates for example?) What can go wrong? (If there is a hole in the IBC the thought of bleach squirting out under pressure frightens me!) Are there any safer alternatives? (Surely the IBC's cab be gravity fed into the storage vessels or simply pumped into the vessel? or the supply can be delivered in a tanker to be pumped in to the vessel? Why would the pressurising of the IBC be the 'preferred method?) That should keep some of you busy on the Wednesday Afternoon! Cheers Tyler

Posted By John Webster As a technique, this is a common way to transfer fluids from one tank to another, particularly where gravity feed is not always possible (your supplier may well deliver to other premises). With aggressive chemicals it avoids use of pumps which may fail, leak, require maintenance etc. Often it is done just to assist gravity with more viscous fluids and to overcome air locks in delivery pipework. BUT, it should only be used where the delivery tank and fittings are designed and certified for use at an elevated pressure. If your receiving tank is enclosed and not freely vented, it must also meet the same requirements. If the source of pressurisation (sounds like a nitrogen cylinder in your case) is capable of delivering a pressure greater than the design working pressure of the tank, then the tank must have a relief valve (or bursting disc) capable of venting the full flow of the gas under any concievable fault condition (eg regulator failure). Hope this gives you some idea of what you should be looking for. I would not like to be in the vicinity if a tank of industrial grade hypochlorite ruptured under a head of gas pressure.

Posted By Tyler John, Thanks for this info. I shall be enquiring about this now that you have brought it to my attention. The Sodium Hypo required to be delivered is at a 28% strength so is not 'industrial strength'. What worries me more though is that it has since transpired that the same technique is proposed for 28% Hydrochloric Acid deliveries. Thanks from (a concerned) Tyler.